It is said that not less than 20% of the population has abnormalities in allergic reactions, which are primary causes of asthma, pollinosis, rhinitis and dermatitis, and this has become a social problem. In these allergic reactions, an antigen such as house dust or pollen is bound to IgE, and the resulting complex acts on IgE receptors on mast cells, leading to activation of the mast cells. The activated mast cells release various chemical mediators such as histamine to cause development of allergic reactions and inflammatory conditions.
Thus, it is necessary to use mast cells for development and evaluation of therapeutic agents for allergic diseases. Therefore, to prepare mast cells, induction of differentiation from umbilical cord blood (1) and induction of differentiation from monkey ES cells (2) have been attempted.
In recent years, induced pluripotent stem cells (iPS cells) of mouse and human have been established by introduction of the Oct3/4, Sox2, Klf4 and c-Myc genes into fibroblasts and their forced expression therein (3, 4, 5).
However, there has been no report of successful induction of differentiation of human iPS cells into human mast cells so far.